getresuid, getresgid - get real, effective, and saved user/group IDs
#define _GNU_SOURCE /* See feature_test_macros(7) */
int getresuid(uid_t *ruid, uid_t *euid, uid_t *suid);
int getresgid(gid_t *rgid, gid_t *egid, gid_t *sgid);
getresuid() returns the real UID, the effective UID, and the saved
set-user-ID of the calling process, in the arguments ruid, euid,
and suid, respectively. getresgid() performs the analogous task
for the process's group IDs.
On success, zero is returned. On error, -1 is returned, and errno is set
to indicate the error.
These system calls appeared on Linux starting with kernel 2.1.44.
- One of the arguments specified an address outside the calling program's
The prototypes are given by glibc since version 2.3.2, provided
_GNU_SOURCE is defined.
These calls are nonstandard; they also appear on HP-UX and some of the BSDs.
The original Linux getresuid() and getresgid() system calls
supported only 16-bit user and group IDs. Subsequently, Linux 2.4 added
getresuid32() and getresgid32(), supporting 32-bit IDs. The
glibc getresuid() and getresgid() wrapper functions
transparently deal with the variations across kernel versions.
This page is part of release 5.13 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the latest
version of this page, can be found at https://www.kernel.org/doc/man-pages/.